U.S. patent number 6,464,704 [Application Number 09/885,673] was granted by the patent office on 2002-10-15 for bipolar electrosurgical instrument with replaceable electrodes.
This patent grant is currently assigned to Sherwood Services AG. Invention is credited to Steven Paul Buysee, David Nichols Heard, Jenifer Serafin Kennedy, Kate Ryland Lawes, Robert Luzzi, Mathew Erle Mitchell, Dale Francis Schmaltz, Daniel Lee Trimberger, II.
United States Patent |
6,464,704 |
Schmaltz , et al. |
October 15, 2002 |
Bipolar electrosurgical instrument with replaceable electrodes
Abstract
A bipolar electrosurgical instrument for vessel sealing
comprises first and second members connected by a pivot. A pair of
jaws have opposable seal surfaces that are designed to grasp
vascular tissue and conduct bipolar electrosurgical current
therethrough. Electrodes on the jaws, including the seal surfaces,
are removable and disposable. The jaws of the instrument have
mechanical interfaces designed to accept replacement electrodes.
The instrument further comprises interlocking ratchets designed to
hold a constant closure force between the seal surfaces. Wires
extend from the electrodes along one of the members and are
connectable to an electrosurgical generator.
Inventors: |
Schmaltz; Dale Francis (Fort
Collins, CO), Luzzi; Robert (Boulder, CO), Heard; David
Nichols (Boulder, CO), Buysee; Steven Paul (Longmont,
CO), Lawes; Kate Ryland (Boulder, CO), Trimberger, II;
Daniel Lee (Greeley, CO), Mitchell; Mathew Erle
(Boulder, CO), Kennedy; Jenifer Serafin (Boulder, CO) |
Assignee: |
Sherwood Services AG
(Schaffhausen, CH)
|
Family
ID: |
25514349 |
Appl.
No.: |
09/885,673 |
Filed: |
June 20, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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387883 |
Sep 1, 1999 |
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968496 |
Nov 12, 1997 |
6050996 |
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Current U.S.
Class: |
606/51;
606/50 |
Current CPC
Class: |
A61B
18/14 (20130101); A61B 18/1442 (20130101); A61B
18/1445 (20130101); A61B 2017/2945 (20130101); A61B
2018/00083 (20130101); A61B 2018/00345 (20130101); A61B
2018/00404 (20130101); A61B 2018/00619 (20130101); A61B
2018/0063 (20130101); A61B 2018/126 (20130101); A61B
2018/1432 (20130101); A61B 2018/146 (20130101); A61B
2018/1495 (20130101) |
Current International
Class: |
A61B
18/14 (20060101); A61B 018/18 () |
Field of
Search: |
;606/51,52,41,45,48-50,205,208 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2104423 |
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Feb 1994 |
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CA |
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WO 99/12488 |
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Mar 1999 |
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WO |
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Primary Examiner: Peffley; Michael
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATION
This application is a continuation of U.S. application Ser. No.
09/387,883 filed on Sep. 1, 1999 now abandoned, which is a
continuation of U.S. application Ser. No. 08/968,496 filed on Nov.
12, 1997 now U.S. Pat. No. 6,080,996 both of which are hereby
incorporated by reference in their entirety.
Claims
What is claimed is:
1. A bipolar electrosurgical instrument comprising: a pair of first
and second members each having a jaw member extending from a distal
end thereof and a handle disposed at a proximal end thereof for
effecting movement of the jaw members relative to one another; at
least one electrode having an electrically conductive seal surface
and an insulating substrate, the insulative substrate being
overmolded to capture the electrically conductive seal surface; and
at least one mechanical interface extending from the insulative
substrate which engages a corresponding mechanical interface
disposed on one of the jaw members to secure the electrode to the
jaw member.
2. A bipolar electrosurgical instrument according to claim 1
wherein the insulative substrate includes a forked extension which
engages a corresponding recess in one of the jaw members to secure
the electrode to the jaw member.
3. A bipolar electrosurgical instrument according to claim 2
wherein the recess is dimensioned to engage the forked
extension.
4. A bipolar electrosurgical instrument according to claim 1
wherein the insulative substrate further includes a n alignment pin
which engages a corresponding socket disposed within one of the jaw
members.
5. A bipolar electrosurgical instrument according to claim 1
wherein the electrically conductive seal surface of the electrode
is generally flat to limit current concentration along an edge of
the electrode.
6. A bipolar electrosurgical instrument according to claim 1
wherein the electrode is removably mounted to at least one of the
jaw members.
7. A bipolar electrosurgical instrument according to claim 1
including a pair of electrodes each removably engage a
corresponding jaw members, the pair of electrodes including first
and second wires which are bundled along at least one of the first
and second members.
8. A bipolar electrosurgical instrument according to claim 1
wherein the electrode includes a strain relief member.
Description
FIELD OF THE INVENTION
This invention relates to a bipolar electrosurgical instrument, and
more particularly to a bipolar electrosurgical instrument having
replaceable electrodes for sealing vessels and vascular tissue.
BACKGROUND OF THE DISCLOSURE
A hemostat is commonly used in surgical procedures to grasp,
dissect and clamp tissue. It is typically a simple pliers-like tool
that uses mechanical action between its jaws to constrict vessels
without cutting them. It is also typical to have a interlocking
ratchet between the handles so that the device can be clamped and
locked in place.
Many hemostats are used in a typical open-surgical procedure. Once
vascular tissue has been clamped with a hemostat, it is common for
a surgeon to tie a suture around the tissue to close it off
permanently prior to removing the hemostat. Several hemostats may
be left in the surgical field until the surgeon has the opportunity
to tie a suture around each section of clamped tissue.
Neurosurgeons have used bipolar instruments to coagulate vessels in
the brain that are smaller than two millimeters in diameter. These
bipolar instruments are typically tweezers-like devices with two
arms that can be deflected toward each other to grasp tissue.
However, it has been found that these instruments are not capable
of sealing blood vessels with diameters larger than about two
millimeters. There has been a long-felt need for an easy way to
seal larger vessels and vascular tissue bundles without the need
for sutures.
It is thought that the process of coagulating small vessels is
fundamentally different then vessel sealing. Coagulation is defined
as a process of desiccating tissue wherein the tissue cells are
ruptured and dried. Vessel sealing is defined as the process of
liquefing the collagen in the tissue so that it crosslinks and
reforms into a fused mass. Thus, coagulation of small vessels is
sufficient to permanently close them. Larger vessels need to be
sealed to assure permanent closure.
A number of bipolar electrosurgical forceps and clamps are known in
the field. However, these instruments are not designed to apply the
correct pressure to a blood vessel to achieve a lasting seal. All
of these instrument also suffer from the drawback that they do not
combine the simplicity and familiarity of a hemostat with a bipolar
electrosurgical circuit.
An example of a bipolar electrosurgical power curve for vessel
sealing is disclosed in a U.S. Patent application entitled, "Energy
Delivery System for Vessel Sealing," Ser. No. 08/530,495, filed
Sep. 19, 1995, and is hereby incorporated by reference and made a
part of this disclosure.
A U.S. Patent application entitled, "Vascular Tissue Sealing
Pressure Control and Method," Ser. No. 08/530,450, filed on Sep.
19, 1995, discloses another surgical tool for sealing vessels, and
is hereby incorporated by reference and made a part of this
disclosure.
U.S. Pat. No. 371,664 discloses a pair of electric forceps with
positive and negative electric poles located on the jaws.
U.S. Pat. No. 728,883 discloses an electrothermic instrument in
which electricity is used to heat one of the jaws of the
instrument.
U.S. Pat. No. 1,586,645 disclose; a bipolar instrument for
coagulating tissue.
U.S. Pat. No. 2,002,594 discloses a bipolar laparoscopic instrument
for treating tissue, whereby coagulation and cutting of tissue can
be performed with the same instrument.
U.S. Pat. No. 2,176,479 discloses an instrument for finding and
removing metal particles. The jaws of the instrument are designed
to complete an electrical circuit when conductive material is
placed therebetween. An insulated pivot and an insulated ratchet
are used to prevent a short circuit.
U.S. Pat. No. 3,651,811 discloses a bipolar electrosurgical
instrument for cutting and coagulating tissue.
U.S. Pat. No. 4,005,714 discloses bipolar coagulation forceps with
jaws that open and close by way of an actuating sleeve.
U.S. Pat. Nos. 4,370,980 and 5,116,332 disclose an electrocautery
hemostats wherein the hemostatic clamping function and the
electrocautery function may be accomplished with a single
instrument. Monopolar electrosurgical designs are shown and
described.
U.S. Pat. No. 4,552,143 discloses a family of removable switch
electrocautery instruments, including an electrocautery hemostat.
Monopolar electrosurgical designs are shown and described.
U.S. Pat. No. 5,026,370 discloses an electrocautery forceps
instrument having an enclosed electrical switching mechanism.
Monopolar electrosurgical designs are shown and described.
U.S. Pat. No. 5,443,463 discloses coagulating forceps having a
plurality of electrodes.
U.S. Pat. No. 5,484,436 discloses bipolar electrosurgical
instruments for simultaneously cutting and coagulating tissue.
The article, "The Mechanism of Blood Vessel Closure by High
Frequency Electrocoagulation" discloses experiments upon the blood
vessels of dogs. The sentence starting on the last line of page 823
describes "an electrode forceps, each of the blades being insulated
form the other and each connected to a terminal of the high
frequency generator."
The article, "Studies on coagulation and development of an
automatic computerized bipolar coagulator" discloses on page 150
that, "It was not possible to coagulate safely arteries with a
diameter larger than 2 to 2.5 mm." On page 151, line 5, it is noted
that "Veins can be coagulated safely up to a diameter of 3 to 4
mm."
Russian Patent 401,367, translation enclosed, discloses a bipolar
instrument with a linkage that brings the working jaws together in
a parallel manner.
Prior disclosures have not provided a design for a bipolar
electrosurgical instrument with removable electrodes capable of
conveniently applying a constant pressure, from a calibrated
spring-loaded source held by a ratchet, that is sufficient to seal
vessels and vascular tissue.
SUMMARY OF THE INVENTION
It is the general object of this invention to provide a bipolar
electrosurgical instrument or sealing vessels and vascular tissue.
The instrument is designed to grasp and clamp vessels or vascular
tissue between its jaws. The jaws have removable electrodes that
are electrically connected to an electrosurgical generator.
Electrosurgical current flows through the clamped tissue between
the electrodes. The instrument is bipolar because electrosurgical
current flows from one electrode, through the tissue, to another
electrode, and both electrodes are located on the instrument. In
contrast, a monopolar instrument requires a separate electrode
(sometimes called an "neutral electrode") that is located remote
from the instrument.
One of the advantages of the instrument is that vessels and
vascular tissue can be sealed without the use of sutures, staples,
or other material that is foreign to the tissue.
Another advantage of the instrument is that the removable
electrodes provide safety against electrical shocks and bums.
Electrically insulative materials, such as plastics, can be damaged
or compromised by repeated sterilization cycles. It is also
possible for electrical insulation to be cut or nicked by sharp
surgical tools. Removable electrodes provide a safety advantage
because they can be replaced prior to each procedure. The
electrodes can also be replaced at any tune if the surgeon suspects
an electrical insulation failure. This advantage is particularly
important for vessel sealing instruments because currents up to 4
amperes may be used.
The present invention is a bipolar electrosurgical instrument
comprising first and second members having first and second jaws
near a distal end, and having first and second handles near a
proximal end. A pivot joint connects the first and second members
to allow for arcuate motion of the first and second jaws toward
each other. First and second mechanical interfaces are located
respectively on the first and second jaws. The first and second
mechanical interfaces are preferably shaped to removably mate with
first and second electrodes. The mating portion of the electrodes
are made from an insulative material to prevent electrical
conduction to the members. Seal surfaces on the opposable
electrodes are preferably designed to clamp vessels and vascular
tissue and conduct electrosurgical current therethrough in a
bipolar circuit. First and second interlocking ratchets are located
on the proximal end of the members to provide a constant closure
force between the seal surfaces.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a bipolar electrosurgical
instrument showing the electrodes mated together in parallel
opposition.
FIG. 2 is a perspective view of a bipolar electrosurgical
instrument, showing one electrode removed with the socket in view,
and one electrode in place.
FIG. 3 is a perspective view of a bipolar electrosurgical
instrument, showing one electrode in place and one electrode
removed.
FIG. 4 is a bottom view of a replaceable electrode showing the
electrically insulative substrate with a portion of a wire
attached.
FIG. 5 is a side view of FIG. 4.
FIG. 6 is a detail view of a forked snapfit extension.
FIG. 7 is a perspective view of a replaceable electrode.
FIG. 8 is side view of an electrode showing a forked snapfit
extension.
FIG. 9 is a partial side view of a portion of a socket designed to
receive the snapfit extension.
FIG. 10 is a partial side view of an electrode seated in a
socket.
FIG. 11 is an enlarged view of a portion of a snap-fit extension
seated in a socket.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIG. 1, a bipolar electrosurgical instrument 10 is
shown with replaceable electrodes 11 and 12 for sealing vessels and
vascular bundles. The instrument 10 comprises a first member 13 and
a second member 14 that are connected at a pivot joint 15. Handles
16 and 17 are located generally at the proximal end 18. Jaws 19 and
20 are located generally at the distal end 21. Sockets 22 and 23
are located on the jaws 19 and 20. The sockets 22 and 23 each
preferably comprise several features, as shown in FIG. 2 at the
location where the electrode 11 is removed. In one embodiment,
shown in FIG. 1, the jaws 19 and 20 are straight. In alternative
embodiments, the jaws 19 and 20 may be curved to accept curved
electrodes 11 and 12, as shown in FIG. 4.
The first and second electrodes 11 and 12 are removably mounted
respectively in the first and second sockets 22 and 23. While the
term socket is used herein, it will be understood that either a
male or female mechanical interface may be used on the jaws 19 and
20, with a mating mechanical interface on the electrodes 11 and 12.
In FIG. 2, one of the sockets 22 is shown with the electrode 11
removed. FIG. 3 shows the socket 23 with an electrode 12 mated
therein.
Each of the first and second electrodes 11 and 12 has an
electrically conductive seal surface 24 and an electrically
insulative substrate 25, as shown in FIGS. 5 and 7. Each substrate
25 is shaped to engage one of the first or second sockets 22 or 23
with mating features that fit removably within the sockets 22 or
23. In the preferred embodiment, the seal surfaces 24 are
relatively flat to avoid current concentrations at sharp edges, and
to avoid arcing between high points.
First and second wires 26 and 27 are connected to the first and
second electrodes 11 and 12, respectively, as shown in FIGS. 1, 4,
5, and 7. In the preferred embodiment, the wires 26 and 27 are
bundled together along one of the members 13 or 14 from the
proximal end 18 to the pivot 15. Near the pivot 15, the wires 26
and 27 are separated and connected each to its respective electrode
11 or 12. This arrangement of wires 26 and 27 is designed to be
convenient for the surgeon so that there is little interference
with the manipulation of the instrument 10. The wires 26 and 27 are
preferably terminated in a connector 2 near the proximal end 18,
although in another embodiment the wires 26 and 27 may extend all
the way to an electrosurgical generator. In an alternative
embodiment, the wires 26 and 27 each extend along a separate handle
16 or 17.
First and second ratchets, 29 and 30, are located on the members 13
and 14 near the handles 16 and 17, as shown in FIGS. 1, 2, and 3.
The ratchets 29 and 30 interlock in at least one position, shown in
FIG. 1 at 31. In the preferred embodiment, there are several
interlocking positions. The ratchet position 31 holds strain energy
in the first and second members 13 and 14 to force the electrodes
11 and 12 against each other in opposition.
Each member 13 and 14 is preferably designed to deflect in a shank
portion, defined as the section between the pivot 15 and the
location of the ratchet. The jaws 19 and 20 are preferably more
rigid than the shank portions. A lateral deflection of the shank
portion causes strain due to bending that behaves like a spring.
The strain energy that is stored in the shank provides a constant
closure force between the electrodes 11 and 12. A design without a
ratchet requires the surgeon to hold the electrodes together by
applying a constant squeeze to the handles. It has been found
through experimentation that a constant force throughout the
sealing process will yield a more predictable surgical outcome. It
is difficult to hold a constant force by hand, therefore a ratchet
in combination with a deflectable shank mill provide a better
surgical outcome.
The electrically insulative substrate 25 on each of the electrodes
11 and 12 is preferably made from an injection moldable plastic.
The substrate 25 is preferably overmolded to capture the
electrically conductive seal surface 24, as shown in FIG. 8. Wires
26 and 27 are electrically connected to the seal surface 24 of each
electrode 11 or 12. There is preferably a strain relief feature 33
on the electrodes 11 and 12, as shown in FIGS. 4 and 7.
The substrate 25 preferably comprises a forked snap fit extension
32 as shown in detail in FIG. 6. Each jaw 19 and 20 has a socket 22
and 23 that comprises a recess 34, shown in FIG. 9, shaped to
capture the forked snap fit extension 32. One of the advantages of
this design is that manufacturing tolerances can be accommodated by
the snap fit as shown in FIG. 11. The preferred embodiment also
comprises a pair of alignment pins 37 and 35 that fit into the
sockets 22 and 23.
In the preferred embodiment, the instrument 10 is designed so that
the electrodes 11 and 12 meet in parallel opposition. Thus,
opposing seal surfaces 24 meet each other in the same plane, as
shown in FIG. 1. In an alternative embodiment, the seal surfaces
can be slightly biased to meet each other at the distal end, and
further closure force at the handles will cause the seal surface 24
on each electrode 11 and 12 to deflect together in the same plane.
In certain embodiments, there may be a stop to create a fixed gap,
preferably about 0.3 millimeters, to prevent shorting of the
electrodes. Other embodiments have an insulative element on each
jaw that opposes the conductive seat surface 24 on the opposing
jaw, such that the instrument 10 does not short circuit when the
jaws 19 and 20 are closed together.
It has been determined experimentally that the closure force
between the seal surfaces 24 is preferably sufficient to overcome a
tendency of the tissue to expand during heating. The sealed tissue
thickness must be less than the initial tissue thickness, under
pressure, in order to create a fused vessel wall. The amount of
pressure required depends on the type of tissue, and the dimensions
of the seal surfaces 24, and the size of the tissue that is grasped
with the instrument 10. The pressure is expressed herein as a
formula depending on the width of the seal surface and the closure
force between the seal surfaces.
For an instrument designed for abdominal vessels and vascular
bundles, each seal surface 24 has a width that is preferably in the
range of 2 to 5 millimeters, and a length in the range of 10 to 30
millimeters. For abdominal vessels and vascular bundles,
experimental results indicate that good vessel sealing performance
can be achieved when the instrument 10 is calibrated to have at
least one ratchet position 31 set such that the closure force (in
grams) divided by the width of the seed surface (in millimeters) is
in the range of 400 to 650, and most preferably 525. For example,
an instrument with a seal surface width of 4 millimeters would
preferably have a closure force of 2100 grams.
For an instrument designed for thick connective tissues and
ligaments, particularly a hysterectomy style Heaney device, the
closure force (in grams) divided by the width of the seal surface
(in millimeters) is in the range of 1000 to 2000. Such an
instrument would also preferably have a cross hatched or knurled
seal surfaces 24 to improve grasping capability, but the height of
the roughness features should be minimized to avoid arcing.
While a particular preferred embodiment has been illustrated and
deck the scope of protection sought is in the claims that
follow.
* * * * *